Study of the Retinochoroidal Circulation with Fluorescein Angiography in a Rodent Orthotopic Whole Eye Transplantation Model
Chiaki Komatsu, MD1, Jila Noori, MD1,2, Maxine R. Miller, MD1, Yong Wang, MD1, Touka Banaee, MD1, Bing Li, MD1, Joshua Barnett, BS1, Wendy Chen, MD, MS1, Kira L. Lathrop, MAMS2,3, Ian A. Rosner, BS1, Wensheng Zhang, MD1, Mario G. Solari, MD1, Joel S. Schuman, MD4, Andrew W. Eller, MD2, Kia M. Washington, MD5,6.
1University of Pittsburgh Medical Center, Department of Plastic Surgery, Pittsburgh, PA, USA, 2University of Pittsburgh Medical Center, Department of Opthalmology, Pittsburgh, PA, USA, 3University of Pittsburgh, Swanson School of Engineering, Department of Bioengineering, Pittsburgh, PA, USA, 4New York University Medical Center, Department of Ophthalmology, New York, NY, USA, 5University of Pittsburgh Medical Center, Departments of Plastic Surgery, Ophthalmology, Orthopedic, Pittsburgh, PA, USA, 6VA Pittsburgh Medical Center, Pittsburgh, PA, Pittsburgh, PA, USA.
Whole eye transplantation (WET) could potentially provide a viable optical system to people worldwide with irreversible vision loss. As a first step toward realizing this goal, we have developed an orthotopic model for whole eye transplantation in the rat. Given that viability of the retina is crucial to functional visual return, we evaluated the structural integrity of the retinochoroidal circulation after transplantation using fluorescein angiography (FA), which is the gold standard to evaluate retinal circulation.
Brown Norway rats underwent syngeneic whole eye transplantation (n=4). Animals were examined at post-operative week 1. Wide-field FA images and fundus photographs were obtained to evaluate retinochoroidal blood flow. Ocular examinations were performed by an ophthalmologist with retina specialization to evaluate the anterior and posterior segments of the eye. A second group of na´ve Brown Norway rats (n=3) served as controls.
FA imaging revealed that two of four rats had transplanted eyes that exhibited normal choroidal flush and arterial and venous filling patterns, normal optic disc appearances, normal retinal vessel caliber and no retinal vessel leakage comparable to the eyes of control animals. Taken together with the results of ocular exams and interpretation of fundus photographs, it was confirmed that there were no signs of retinal ischemia, vessel narrowing or arteritis/phlebitis present in the eyes of these animals. The remaining two of four rats with transplanted eyes showed normal choroidal, arterial and venous filling patterns and no signs of arteritis/phlebitis or vessel leakage, however attenuated retinal vessels were seen on color fundus photographs and FA imaging in the study eyes. Correlated with ocular exam results and evaluation of the retina as captured on fundus photographs, there appeared to be decreased retinal perfusion in these animals as compared to controls.
FA results have confirmed that retinochoroidal blood flow can be established after WET in a rat model. Two of the transplanted rats displayed no difference in retinochoroidal circulation as compared to the eyes of control animals. The remaining two rats with transplanted eyes appeared to have decreased retinal perfusion. In all rats, the pattern of vascular filling was normal, and the absence of vessel leakage indicates that the structural integrity of ocular blood vessels can be maintained after WET. The etiology of vascular attenuation and presumed decrease in retinal perfusion will be investigated in future studies.
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